1. Field of the Invention
The present invention relates to a voltage converting device, and more particularly, to a voltage converting device capable of adaptively adjusting the pre-charge current according to the output loading.
2. Description of the Prior Art
Electronic devices are usually comprised of many different elements, which operate with different operational voltages. It is necessary to utilize different DC-DC voltage converters in order to achieve different voltage modulations, such as modulation for raising voltage values or degradation voltage values, and to maintain predetermined voltage values. Many types of DC-DC voltage converters which are widely employed are derived from the buck/step down converter or the boost/step up converter. The buck converter can decrease an input DC voltage to a default voltage level, and the boost converter can increase the input DC voltage to another default voltage level. Both the buck and boost-type converters have been varied and modified to different system architectures and requirements.
In the conventional boost converter, an output voltage of the output end of the boost converter must be greater than the input voltage of an input voltage of the input end for allowing the boost converter to work normally. Thus, the conventional boost converter needs to perform a charging process when starting operating, for making the output voltage of the output end become greater than the input voltage of the input end before entering the normal operation process. However, if the loading coupled to the output end of the boost converter exceeds the loading capability of being driven by the predetermined charge current in the boost converter, the charging process may work abnormally, resulting in the output voltage cannot exceed the input voltage. As can be seen from the above, the prior art needs to be improved.